Nasa, post apollo and the rise of the space shuttle - a glance at the definit...
JBIS_1989-2
1. llPWIOJEIW I
journal of tt,e
BIS britist, interplanetary society
Vol.42 No. 2
ISSN 0007-084X
MANNED SPACE CAPSULES
PUBLISHED MONTHLY IN LONDON
FEBRUARY 1989
(47)
2. JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY
EDITORIAL ADVISORY BOARD
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lished continuously since 1934 and has appeared monthly since 1970: Each annual VOlume contains between 500-
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DR. R.W. HOLDAWAY
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DR. D.W. HUGHES
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PROF. J.D. ROSENDHAL
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4. An MRC Rescue Capsule leaves the Freedom Space Station and begins re-entry into the Earth's atmosphere. (NASA)
50
5. Journalofth� British lnl�rplan�tary Society. Vol. 42, pp. 51-57. 1989
MULTI-ROLE CAPSULE- AN INTRODUCTION
C.M. HEMPSEll
British Aerospace, Space and Communications Division, Stevenage, Herts, England.
Despite the introduction of more sophisticated re-entry systems such as the Space Shuttle, there is still a role in the
space infrastructure for manned semi-baUistic capsules. The Multi-Role Capsule (MRC) study explored the potential
of such capsules i n a European and international context.
This introductory paper presents the background to the MRC study, reviewing the various in'frastructure roles for
capsule and discussing other capsule concepts currently under evaluation. lt also presents the main -comments
received by the study team since the results of the sudy were made public.
1. INTRODUCTION
This special issue of the JBIS is devoted to a presenta
tion of the results of the Multi-Role Capsule (MRC) study.
This independent study reviewed the potential for man
ned capsules of the type extensively employed by the
American and Russian programmes in the 1960s and still
used by the Soviet Union as the means of transporting
men to and from the space environment. Despite the
advent of more advanced re-entry systems such as the
Space Shuttle, the simplicity and mass efficiency of
capsules still makes them the optimum technical
approach in many applications.
This i ntroductory paper starts by exploring'the back
ground to the MRC Study in terms of the concerns of the
study team. That is ttie areas of space activity in which it
was foreseen that capsules could play an important role
and the proposals (capsule or otherwise) which had
been made to fulfil! those roles. The paper then presents
a brief outline of the MRC study results and concludes
with a discussion of some of the main comments that
have been made regarding the study's cenclusions since
they were made public at the IA.f conference in Brighton
last October (1987).
2. BACKGROUND
Before considering the Multi-Role Capsule concept, one
sflould consider the background that was under consid
eration during the project's genesis. The team that
generated the concept were concerned about aspects of
both the American and European infrastructure, and four
main areas were investigated:
(i) European manned space infrastructure;
(ii) European microgravity requirements;
(iii) An escape system for the US/International Space
Station;
(iv) An escape system for a European space station.
This section considers each of the areas in turn. The
discussion reflects the most recent events at the time of
writing (at the conclusion of the study). However this
update does not significantly alter the main concerns
that influenced the MRC study team and the subsequent
events have only put the proposal into a clearer context.
2.1 European Manned Space Infrastructure
Over the past four years there has been an increasing
acceptance within the European space community that
Europe must undertake the development of a manned
infrastructure if it wishes to improve its ability to exploit
the space environment. This belief. has led to the
establishment of the Columbus and Hermes program
mes, Columbus providing the in-orbit elements and
Hermes providing the manned transportation system to
reach them.
The Columbus programme originated as a German/
Italian study which explored in some detail by expand
ing the-Spacelab technology and hardware to provide a
permanent orbiting laboratory. The results of these
national studies were widely -reported and the conclu-
. sions, and the rationale behind them, were well under
"'stood by the European Space community generally
when the American offer to join the Space Station
programme was made. The national study could then
form the basis of a European wide programme that
elegantly combines exploitation of the opportunity cre
ated by cooperation on a major American programme
with the establishment of a n autonomous European
facility.
lt is perhaps somewhat unfortunate that many of these
· desirable features found in the Columbus programme
history were not also to be found in the Hermes
programme. Hermes originated in national studies con
ducted by France but unlike Columbus, the results of
early study work were not so widely disseminated, and
many of the fundamental conclusions have not been
fully justified. Even the choice of approach remains
unexplained: of the three alternatives, .
(i) Capsule on a general purpose launcher;
(ii) Winged aerospaceplane on a general purpose laun
cher;
(iii) Specialist manned launch system,
the Hermes study selected the winged aerospaceplane.
This is a most surprising and controversial choice,
because whereas the other two options have been
successfully implemented, the American X-20 (Dyna
soar) programme (which is the only publicised attempt
at the second option) failed to meet even the most
modest objectives.
Hermes has also not managed the happy trick of
contributing to the overall infrastructure as w�ll as
51
6. enhancing European autonomy. lt has not found any
role in the context of the Space Station programme and
it has even had some difficulty in managing the servicing
roles in the autonomous European infrastructure.
Because of the lack of understanding about Hermes
goals and the logic behind its trade-off decisions, the
examination of alternatives is an effective tool for those
outside the Hermes study team to explore the require
ments and potential technical solutions of the trans
portation element of the European manned infrastruc
ture.
2.2 European Microgravity
One of the main impacts of the "Challenger" loss and
the subsequent grounding of the Space Shuttle fleet was
the delay in launching the European "Eureka" platform
and a lack of flight opportunities thereafter. This has
caused a build-up of European microgravity experi
ments which have no immediate opportunity to fly and
one solution to this problem is the use of capsules.
There are a number of capsule studies underway i n
Europe ·all intended to fly microgravity experiments and
return them to Earth. This type of mission is frequently
flown by both China and the USSR, indeed both
countries are now marketing space on their flights and
have been successful in acquiring European orders.
One of the most mature European proposals is TOPAS
(Transport Operation of micro-g Payloads Assembled on
Scout). This is a German-Italian programme and is
exploring the potential of a small capsule based on an
American (General Electric) design, which would be
placed in orbit by a Scout rocket launched from the San ..
.
Marco platform. The Scout rocket is also American,
being constructed by lTV.
The payload of this capsule wo•1ld be about 1 00 kg and
it could remain in ..orbit for be.ween 2 days and two
weeks. The capsule would then re-enter and parachute
to a land recovery. Possible recovery sites include the
Sahara, Saudia Arabia and Australia.
TOPAS has a limited capability primarily due to the
restrictions placed on the system by the Scout launcl:)er.
Both Germany and Italy have study programmes under
way to consider the next step.
Aeritalia (Italy) have been considering a concept that
would be launched by an uprated version on the Scout
giving about twice the payload. This capsule is called
Carina.
Carina is cone shaped re-entry vehicle 1250 mm in
diameter and 1 350 mm high. The payload mass is 150 kg
and the capsule can provide 150 Watts of power for the
m_ission life of up to 21 days. Power is supplied from a
combination of solar arrays and batteries. The system
would also provide 150 kbps telemetry and an on-board
memory capability of 128Mb.
A German study, lead by Dornier Systems, has
examined � larger capsule concept called Raum-Kurier
(Space Courier). The capsule is a "Gemini" type cone 2
meters in diameter and weighing 1 .1 tonnes. lt is
launched into a 300 km 55° inclination orbt for 7 days. A
solid propellant retromotor initiates the recovery, return
is on-land and uses conventional parachutes. The
payload weighs 600 kg and has 0.7 m3 volume. lt is
supplied with 150 Watts of power and has a data rate of
2 kbps. launch systems options are being left open with
China's long March looking favourite for the early
launches. The USSR and the American AMROC are also
potential options.
Raum-Kurier is seen as the starting point for the
longer-term exploitation of capsule and re-entry technol-
52
ogy. The design incorporates growth capability with
respect to unmanned and manned utilization such that
by a step-by-step learning process improved capsules
can be developed with minimization of development risk
and development costs. A possible improvement of the
unmanned capsule would be to add an expendable
solar power module to the baseline design to allow
longer mission durations. The manned capsule design
will be characterized by higher safety requirements and
perhaps lift-controlled entry trajectories to improve the
oberational flexibility and to decrease the loads.
There are common features to all these proposal
which limit their effectiveness as complete microgravity
laboratories. The payload on all is small, the best is
Raum-Kurier which has half the payload of Eureca The
flight times are limited to a couple of weeks. None is
capable of flying biological experiments or the large
packages needed by some materials experiments.
However the need for any microgravity capability as
soon as possible is now so pressing that at least one of
these systems is likely to be developed.
2.3 US Space Station Escape Vehicle
In the renewed examination of Space Station safety in
the light of the lession learnt from the Challenger
accident, NASA proposed that an Escape Vehicle be
added to the Space Station. This contingency facility
would to an extent replace the safe haven philosophy
(which had been the earlier approach) and gives greater
coverage of possible contingency situations including:
• Return of injured or ill crew members.
• Escape from a severely damaged station.
• Return capability in the event of loss of STS oper
ational status.
The Escape Vehicle is designated Crew Emergency
Return Vehicle (CERV).
Having identified a requirement to be able to evacuate
the Space Station Crew in the event of an emergency
there are a number of alternative approaches.
The MRC study considered that an escape vehicle
permanently attached to the Space Station represented
the most attractive a pproach. The study identified four
other possible approaches open to NASA and these are
summarised below:
Approach (1} Modified Apollo Modules
Technical Risks: Major Refurbishment; almost com
Cost:
Operational:
Advantages:
Conclusions:
plete rebuild.
New Service Module; new Docki ng
Adaptor; refurbishment; overall cost
close to baseline system.
Atmosphere
incompatability;
Parts and spares
availability; No
expansion capability.
Proven re-entry system.
Many technical problems and little cost
reduction.
Approach (2) Permanently Attached Orbiter
Technical Risks: Modify arbiters for six months- orbit
staytime.
Cost: New Orbiter; Orbiter Mods to e1'Cire
fleet; overall cost signif�candy greiller
than baseline system; all the inaiiCiial
impact of five arbiter fleel -- cap.:-
7. Multi-Role Capsule-An Introduction
OperationaI:
Advantages:
Conclusions:
ity unchanged.
·only one arbiter attached and if used
as ambulance remaining crew have no
escape; station· crew must contain two
shuttle pilots; little expansion compati
bility.
Proven re-entry system.
More expensive and has operational
problems.
Approach (3) $!1uttle Rescue Mission
Technical Risks: No major risks.
Operational: Two week plus delay before reaching
the station; no capability if Shuttle
System is grounded.
Advantages: Almost no cost impact; proven re
entry system.
Conclusions: Delay lime unacceptable in almost
every hazard situation ; lack of system
level redundancy also a problem.
Approach (4) Ground Launched CERV
Technical Risks: Modify an EV for CERV delivery.
Costs: Overall cost comparable to baseline.
Operational: Delay time of around two weeks (as
Advantages:
Conclusions:
bad as a Shuttle rescue mission).
Reduction in nominal delivery costs.
Delay time unacceptable in almost
every hazard situation.
All these other approaches were judged to have serious
if not insurmountable problems. NASA's studies seem
to be coming to similar conclusions although at the time
of writing these were still under evaluation and a final
decision had not been arrived at.
There is a considerable background of work in the
United States addressing "From Orbit" escape systems.
A revi�w in "Space Station Crew Safety Alternatives
Study" [1] identified 13 past proposals from US com
panies. These fall into two classes: deployable devices
where the heat shield is in some way depluyad (e.g. by
inflation or unfurling) and rigid where the escape system
is a conventional homogeneous system: Most of these
proposals date back in concept to the 1960s and tend to
suffer the same problems in the light of Space Station
evacuation:
• They are for only one or two crew members com
pared with an initial Space Station crew of eight.
• They required new technology development (espe
eially the deployable types).
• They are somewhat crude devices putting the crew
member at higher risk than would normally be
acceptable.
Three of these concepts are worth further attention
because derivatives of them are being proposed for
CERV. Firstly there is the Apollo Escape concept consist
ing of a modified Command Module. A rescue version of
the Apollo was produced for the Skylab programme by
modifying a CM/SM such that it could catry five men. In
the-event thatlha.tra.nsport Apollo attached to Skylab
was unable to return, the rescue Apollo would fly to the
station with a crew of two an.d pick up the three men
stranded in orbit and return to Earth: Problems on the
second manned mission actually lead to the first stages
of launching this rescue craft, although in the event it
was not required. .
The General Electric MOSE system was considered in
the mid-seventies. lt was a very simple system adapted
from the Discovery type of capsule which has been
extensively used on American programmes. In the light
of actual Space Station requirements a more sophisti
cated version providing a shirtsleeve environment and
accommodating six men is under evaluation.
The third proposal which is under consideration is the
use of a lifting body (or a winged vehicle). This has the
advantage of a lower g level on crew members which
can be beneficial if injuries have been sustained. lt also
allows a runway landing which would speed access to
medical facilities again if injuries or illness were
involved. The disadvantage is the additional cost of the
system, the technology problems associated with in
orbit storage, and the complexity in flying the system.
The NASA studies have explored the capsule require
ments. The basic requirements are for an Escape Sys
tem, a safe haven and a method of returning ill or injured
crew members. Based on the experience of Antarctic
bases and submarines it is estimated a crew member
will need to be evacuated from the Space Station on
average once every 4 years.
A number of other missions were also identified.
These were all related to contingency situations such as
recovery of a stranded EVA astronaut or a backup-crew
delivery-system should the STS system be grounded for
any period. These additional missions are still unde·r
examination.
2.4 European Space Station Studies
Europe's first manned space programme was Spacelab
which is a pressurised laboratory which flies within the
payload bay. When the Americans offered involvement
ih the Space Station Programme the most logical
contribution was to modify the Spacelab system to
provide a laboratory module which would attach to the
Space Station allowing much more experimental time
and space. A further development would be the
• attaching of a resource module to a pressurised labo,a
tory to create a Man-Tended Free Flying (MTFF) facility.
As already discussed these two laboratories form the
basis of the Columbus programme.
However, the Columbus programme will fall short of
being an autonomous European Space Station which
would demonstrate a complete capability in manned
spaceflight and provide guaranteed European access to
the Space environment. Two ESA funded studies have
been conducted to explore developing Columbus tech
nology to produce an independent European Spac.e
Station. These are the "Long Term Evolution" (LTE)
study and the "Study Towards European ·Autonomous
Manned Spaceflight" (STEAMS).
2.4.1 Long Term Evolution Study
The "Study on Longer Term Evolution Towards Euro
pean Manned Spaceflight" was conducted for ESA by a
team under the leadership of MBB/ERNO. lt examined
the requ irements for an autonomous European Space
Station and included an examination of the escape
vehicle requirements.
The study performed a requirement breakdown start
ing from the role as Station Rescue System. From this
six ptimary missions were identified :
• Station escape.
• Stranded EVA crewmember rescue.
• Crew rescue from secondary system.
• Attached safe haven.
• Detached safe haven.
53
8. • Contingency crew delivery system.
A secondary m ission not related to its safety role was
also identified: this was as a cargo return system at the
end of its life i n orbit. An Escape Veh icle would not
necessarily have to conduct all these m issions to be a
viable system.
A number ·of preliminary designs were generated
covering a range of technical solutions. As a result of
comparing these preliminary design concepts the study
arrived at some preliminary conclusions with regard to
· the escape vehicle:
• Station escape (including ambulance) is an essential
m ission.
• EVA crew member rescue was worth considering
further.
• Rescue mission to systems otHer than Space Station
would need i nfrastructure fevel consideration.
• Attached safe haven had a minor i mpact and was
recommended for i nclusion.
• Detached safe haven was worth considering further.
• Contingency crew delivery has a major impact at
i nfrastructure level and needs careful investigation.
2.4.2 S. T.E.A.M.S.
The "Study Towards European Autonomous Manned
Spaceflight" was conducted for ESA by a team u nder the
leadership of Aerospatiale. like the LTE it considered an
autonomous European Space Station but with a diffe
rent emphasis considering a more direct utilisation of
Columbus elements. lt also considered the requirements
for. an Escape Veh icle and arrived at five m ission options·
(mission having a slightly different meaning in the
context of this study compared with. LTE).
Missions 0-3 were all variants on crew evacuation but
with different degrees of flexibility over aspects such as
relocation, duration and landing philosophy. Mission 4 is
the same as the secondary m ission described in the LTE
study; namely cargo return at end of life.
Unlike the LTE study STEAMS did not consider a range
of system capabilities, rather it centred on a single
approach using a small capsule. Two possible configl.Jra
tions were proposed and Fig. 1 shows the baseline
Fig. 1. Aerospatiale Escape Vehicle Concept
54
design. The study did identify a num� of critical
technology issues related to the Escape Vehlde these
were:
E. V. LIFE DURA TION:
- Monitoring/maintenance of critical components
(activation readiness should be permanent!.
- Ageing of materials for re-entry capsule 1thermal
shield, structures etc).
E. V. ROBUS TNESS and RELIABILITY:
- E.V. should be able to operate in aggressive environ
ment (alert/evacuation phase).
- Reinforced. hardened and reliable design.
E.V. LOW WEIGHT/LOW COST:
- Simplicity of design.
E. V. "AMBULANCE" FUNCTION:
- Medical support inside a small vehicle.
- Acceleration/shocks limitation (aerodynamic shape,
landing system).
2.4.3 Further Studies
European work on space station Es�ape systems is
continuing with a special ESA funded study devoted to
an "Escape Vehicle for the Autonomous Presence of
Man i n Space". This study has just started u nder the
industrial leadership of Aerospatiale with MBB and
CASA as study participants. This work should refine the
requirements for escape systems from the European
infrastructure viewpoint and identify the technology and
financial factors that need to be aodressed.
3. MULTI-ROLE CAPSULE OVERVIEW
lt was a discussion of the above background that lead a
group of British Aerospace engineers to propose
examination of a manned vehicle with a multi-role
capability. The i ntention was that this would be able to
fulfil many of the European requirements for the 1990s
and also provide a valuable contribution to the USA
Space Station Programme in addition to Columbus
elements. The study was started in April 1987 and the
Fig. 2. MRC on Orbit View
9. Multi-Role Capsule-An Introduction
bulk of the work was completed in about six months. The
results were presented at the IAF conference· in Brighton
in October 1987.
The study centred on a semi-ballistic capsule concept
similar in many respects to American manned spacecraft
of the 196Ca but employing more advanced avionics and
structures technologies_ The configuration, shown in
Figs. 2 and 3, featured a conical re-entry vehicle with a
Fig. 3. MRC Internal View
TABLE 1. MRC Design Features.
Mass
Size
Crew
Payloact
Life
Recovery
7 tonnes i n orbit.
4 m diameter 8.3 m long (solar array
deployed)
4 normal, 6 escape
250-500 kg (carried i n cabin) (1500 kg
unmanned m icrogravity)
5 day active (+ 1 day contingency) >2 years
on-orbit store
Semi-Ballistic re-entry; parachute to ocean
splashdown
The capsule was designed to be launched into Low
Earth Orbit by Aria ne 4. After a mi.ssion of up to five days
it would re-enter the Earth's atmosphere. The conical
shape together with an offset centre of gravity allows the
capsule to fly a semi-ballistic trajectory which lowers the
acceleration forces to about three times Earth gravity
and also permits a degree of control as to where the
capsule lands. After the capsule has completed the high
velocity part of the descent it would deploy parachutes
to slow dovun to a safe speed. lt would splashdown in the
ocean in the same way as the American Mercury,
Gemini, and Apollo capsules. The weight on return is
about 5.5 tonnes. The capsule is divided into two
modules; the Descent Module and the Service Modu le.
The Service Module is a cylinder structure that
attaches to the back of the Descent Module. lt houses a
solar array for the generation of electrical energy and
various communication a ntennas. lt is discarded before
re-entry i nto the Earth's atmosphere.
The Descent Module, which is the only part of the
spacecraft to return to Earth, has three sections. The
forward cabin has a docking port. control thruste;s,
hygiene and galley facilities. The mid cabin houses the
. crew couches and the control equi pment. The rear cabin
• houses the batteries, the propellant and air tanks, and a
payload bay for mounting mission specific equipment.
Space Station standard docking port at the apex. The
study baseline design features are summarised in Table ·
1. Figure 4 shows a comparison between the MAC
concept and past capsule designs.
Three versions of the MAC were identified each
i ntended to fulfil a different role. These were:
Y.2n2!ll uagw Siiiii!J IIWI1
A
IW.i�
g@ B Q-
(_j:..
ORIGIN USSII USA USA USSII USA UK
OPIIRAnONI ·1·., •a .., ..... ., ..... ..
Fig. 4. Capsule Comparison
CRIIW
NORMAL I J I a I· S s
I
•
CONTINGENCY & •
ORIITMASS u .. , •• uo
i
••
!TOIONISI
Un:TIMII • I .. .. 12
I
•
CDAY!II
RIICOVIIRY BALUSTIC BALUSTIC -I BALLISTIC SUIIIALUsnC SIIMIBALUsnC SEMI BALLISTIC
LAND WATU WATU LAND WATER WATU
CONnGURAnON 1111 ENTRY SPHEIIII CAPSULE aarrav MODUu: OIIIIIT MODI/LZ COIOUND MODULE DaCDCTMODULE
+ + + + + +
INSTIIUMENT lll'l1tOPACK MniOMODULII �IIODULII SUVIC! MODULE SEIIVICE IIDDULII
UCTION + +
I!QUIPtii!NT SEIIVICE MQDI/LZ
IIODUU:
55
10. (i) Four-man General Manned Transportation.
(ii) Six-man Escape System.
(iii) An Unmanned Microgravity Laboratory.
Within the depth of definition of the study there was very
little technical difference between the two manned
versions, apart from the number of seats. The unman
ned microgravity version has some differences, mostly
removing equipment not required in this role.
The study outlined a development programme assum
ing the Ariane 4 launcher. The main aim was to explore
the earliest possible operational date, and to demons
trate that the system could be available in a timeframe
compatible with the identified roles on the US Space
Station. A summary of this programme is shown in Fig.
5.- lt assumed a Phase A start at the beginning of 1 988
and leads to the first flights, inclu.ding one manned
flight, in 1 993, ie a total developmen{ programme of just
under six years.
Feasibility Studies
Initial Tech Programme
Systems Design
Detailed Subsystem Design
Detailed System Design
Structure Model Prog
Engng Model Prog
Qualification Model Prog
Flight Model Programme
F1 - Unmanned
F2 - Microgravity
F3 ·Manned
F4- Manned
Phase A_I_ Phase 8 I
C .W Hnr�pse/1
launch system development programme. A more
detailed account of the selection criteria is given in
"Rationale and Requirements for the Multi-Role Cap
sule" a companion paper in this issue.
The launch team appreciated that some modifications .
to the launch system would be required both to
accommodate the_ new payload and more generally to
manrate the launch system. Details of the identified
modifications are discussed in "Multi-role Capsule Sys
tem Description" also a companion paper in this issue.
At the time of the study the team could foresee no
problems in implementing these modifications as they
wer.e essentially the same modifications proposed by
the early Hermes programme (when its launch system
was Aria ne 4). The reasons for the move of Hermes from
Ariane 4 to Ariane 5 were given as the increased mass of
Hermes, which took it well beyo(ld Ariane 4's capability
(even after stengthening), and the bending moments
generated by Hermes on the launcher during the ascent
Phase C J Phase D
I
1988 1989 1990 1991 1992 1993 1994
Fig. 5. Development Programme
4. REACTION TO THE MRC CONCEPT
Since the MRC concept was first revealed to the public at
the IAF conference in Brighton during October 1 987
there has been considerable comment on the proposal.
Many people have been attracted by the relatively low
development cost of the programme, the early oper
ational date and the possibility of a valuable trans
atlantic link. From this point of view there have been
many favourable comments.
However there have also been a number of concerns
expressed about the concept as proposed and three of
these merit consideration in an overview of the MRC
potential:
(i) The selection of the launch system.
(ii ) The selection of the sea-based recovery.
(iii) The extent of technology development.
4.1 Launch Vehicle Selection
The study selected Ariane 4 as a launch system for the
MRC because it allowed for earlier operational flights
and decoupled programme success from a parallel new
56
in the atmosphere. Neither of these problems arose in
the case of the MRC, and the original Hermes work on
Ariane 4 was considered valid.
Discussions since the study was made public have
revealed a concern that the Ariane 4 launch system was
designed as an unmanned system and the reliability was
reduced in accordance with this role to increase the
commercial competitiveness of the vehicle. lt was felt by
some that the degree to which this philosophy had been
applied was such that it would not be practical to raise
the reliability to that required for a manned launch. Thus
the feasibility of the selected launch system must be
considered an open question.
Unfortunately this is not an easy question to resolve as
the only way of establishing the feasibility of man rating
is for the Ariane industrial team to identify those items
that contribute to the comparatively low reliability and
then to identify alternatives that would raise reliability to
a level acceptable for manned ftight. This exercise was
beyond the scope of the MRC study.
While the use of the Ariane 4 must remain in quesbOn
a number of relevant points should be born in mind:
(i) The higher than acceptable failure rate of the Anane
11. Multi-Role Capsule- An Introduction
family has lead to many of ti:Je reliability issues
being addressed in any case.
(ii) None of the Ariane failures has been potentially
catastrophic in the sense that sufficient warning of
the failure would have been available for the crew to
use escape systems and procedures to safely return
to Earth.
(iii) lt is difficult to conceive that there is a fundamental
problem in the Ariane system that· could not be
addressed b; alternative components or increased
inspection and monitoring.
This concern does not effect the suitability of Ariane 4 to
launch the unmanned microgravity version of the MRC.
Nor does the argument apply to manned launches on
the alternative launch systems. Ariane 5 and STS.
4.2 Recovery Operatiens
A second issue which has been queried by a number of
commentators is the selection of sea-based recovery as
opposed to land-based recovery.
The study assumed that recovery could be accom
plished by a single vessel and a helicopter, and that an
entire carrier task force (such as was used in the 1960s
for capsule recovery) would not be required. This
reduction in effort is the result of knowledge about
achievable touch down accuracies which eliminate the
need for any major search operations.
A similar approach has been suggested by NASA's
Johnson Space Center. As part of the CERV programme
they are considering off-shore recovery as opposed to
recovery operations in the deep ocean. The capsule
would descend to within a kilometer of a coastal
recovery facility and the necessary helicopters and boats
can then be sent out to recover the capsule and crew.
The issues raised in connection with sea rer.overy are
the cost and the availability of suitable craft if the use of
national navies are assumed. These are valid concerns
and were not fully addressed by the MRC study and
would require further investigation before a satisfactory
conclusion could be drawn.
. In addition to the general operationaLconcerns there
were some additional comments with regard to the
suitability of a sea recovery when the capsule is used as
a crew ambulance to return injured crew members.
There are three factors to consider:
(i) The time from landing to hospitalization.
(ii-) The difficult handling of i ncapacitated crew mem
bers.
(iii)
-
The adverse and in some cases dangerous effect of
seasickness on certai n inj uries and illnesses.
The current conclusion is that the landing technique
should be judged on open issue. Both sea and land
recoveries have been extensively used and the technical
feasibility of either is beyond doubt. The land recovery
would,. require a small increase in system mass to
accommodate cushioning rockets to soften the final
impact, but this would not be sufficient to alter the
'overall conclusions about the capsule's p'Jtential. A
more detailed study would be required to conduct a
trade-off to find the optimum approach.
4.3 Technology Acquisition
A persistent comment is the lack of technology advance
ment inherent in adopting a capsule approach. Mostly
this comment has been made in the context of prepara
ton for advanced aerospaceplane such as HOTOL. This
subject is covered in "Rationale and Requirements for
the Multi-Role Capsule" (Paragraph 7.5) but one point is
worth emphasising.
There is a widespread perception in Europe that there
is essentially no knowledge and experience in the field of
hypersonics. This is an erroneous view; the military
programmes in both France and Britain have acquired
an extensive background in this technology. For exam
ple the u ncertainties that exist on the HOTOL prog
ramme are confined to the chemical reactions of the
atmosphere with some of the new reusable materials at
the specific conditions HOTOL will experience. This kind
of data can only be obtained by a specialist test vehicle
designed to accurately match the specific re-entry char
acteristics of HOTOL.
The common criticism voiced that Hermes is a essen
tially precursor to a HOTOL type programme whereas an
MRC approach is of no value, is not valid. Neither are an
-essential precursor, indeed the benefit of either is very
small in terms of directly applicable technology.
5. CONCLUSIONS
The MRC study showed that manned capsules still have
many missions that they can effectively perform, both in
a purely European and in an international context. The
feasibility design produced by the study was judged to
have successfully scoped the technical and financial
aspects of such capsules. Indeed it went further and
showed a single design could be expected to undertake
all the roles identified. The approach ·outlined merits
more consideration, particularly by Europe as a means·
qf meeting infrastructure requirements i n a cost effective
manner with low technical risk.
REFERENCES
1. R.L. Peevey, R.F. Raasch, and K.A. Rockoff, Space Station
Crew Safety Alternatives Study ,.. Final Report, NASA
Contractor Report 3854.
This paper represents the author's private work and the views expressed in the paper are those of the author and do not necessarily
represent those of British Aerospace plc.
* * *
57
12. Joumal ofthe British lnterplanetun S.X:c• · .!:_ ::- :...._-.:;_ 191(9
RATIONALE AND REQUIREMENTS FOR THE MULTI-ROLE CAPSULE
C.M.HEMPSELL
British Aerospace plc, Space and Communication Division, Stevenage, Herts.
The Multi-Role capsule (MRC) is a concept for a recoverable capsule capable of working in unmanned and manned
modes. lt would be launched on Ariane 4, and be capable of carrying up to six men or 1 500 Kg of cargo. lt would
undertake a number of roles, supporting space station programmes with crew delivery and emergency crew
return, other missions could include independent manned operations and as an unmanned microgravity laborat
ory. The concept has bet!n the subject of a preliminary study to establish the feasibility and potential. The paper
discusses the reasons whythe MRC study was undertaken and the rationale for setting the system requirements.
1. INTRODUCTION
lt is becoming convential·wisdom within Europe that an
independent manned access to space needs to be
acquired sometime in the 1 990's. The arguments for a
European independent "man in space" programme are
very similar to those for Ariane as an independent
unmanned access, that is reliance on outside launch
capability carries the risk of European priorities being
subordinated to those ofthe launcher nation. lt is not the
intention of this paperto remake the case for a European
manned launch system but to review the approaches
available to achieve this objective and to establish tha
minimum useful requirements on such a system.
The study produced a requirement specification which
embodied the results of the infrastructure investigation
describea above. The feasibility of this specification was
then demonstated by the development of a feasibility
design. This concept for a sem i bal listic capsule is called
the Multi-Role Capsule (MRC).
2. STUDY RATIONALE
2.1 European Infrastructure
There has been considerable study work conducted on an
independent European manned system on the Hermes
programme. Hermes is a winged aerospaceplane
launl:hed on �riane 5, which i8'Specified as being capable
ofcarrying a crew ofthree and a useful payload ofaround
2.1 tonnes.
The study was conducted to re-examine from first prin
ciples the best method of achieving an initial European
manned infrastruct-ure. This has been studied in some
depth by the Hermes project, based around an Ariane 5
launched Spaceplane. There were two reasons for con
ducting the MRC study despite the advanced state of the
Hermes studies.
2. 7. 7 A Changing Role
The first reason is the changing role' of Hermes as the
study progresses. There have been major changes
recently introduced in the Hermes concept most, notably
the deletion of the external cargo bay, and the addition of
a full crew ejection capability. This is primarily a result of
a changing perception of Hermes rofe, it is now primarily
58
seen as a m�ans of servicing Columbus elements, par
ticularly the Man Tended Free Flyer (MTFF) and any inde
pendent European Space Station. Despite the magnitude
of these changes the Hermes concept was not revisited at ·
a fundamental (blank sheet) level.
2. 1.2 Infrastructure Definition
The second reason is a better definition of the rest of the
Infrastructure. At the inception of the Hermes project in
1Q82 there was very little understanding of what other
infrastructure goals Europe would have in the 1990's. Five
years later we have a much clearer picture and so we can
review the effectiveness of Hermes to fulfifl a useful role
in the overall infrastructure.
·
Figure 1 shows a diagram of the main thrust of Euro
pean infrastructure developments in the 1990's. There are
fou r main thrusts to European programme in the 1 990's
these are.
. ...,
·-
Fig.1 European 1990's Infrastructure
·-
• LAIIT
• lA-
Columbus as a part of the NASA space station and as
an independent facility.
ii Expansion ofthe independent European launch Cllpe
bility with Ariane 5.
iii The development of an advanced aerospac.,...•10
13. Rationale and Requirements for the Multi-Role Capsule
ensure Europe continues to have economically com
petitive launch systems in the next century.
iv The estabishment of an independent manned capa
bility.
One of the main objectives ofthe independent manned
capability is to acquire the complete range of
technologies and management skills in Europe to exptoit
as manned spaceflight becomes increasingly important
in the overall space capability of a major space power.
While this objective is independent from the other infras
tructure goals there are significant interactions between
them. These can be summed up as follows:
Launchers: lt is clear that Europe will need to exploit its
existing launch capability (Ariane) for its first indepen
dent manned missions since developing a from scratch
system has neither technical nor economic merit. The
launching of manned systems can be very demanding on
launch systems and the possible impact must be fully
assessed.
Columbus: lt is clearly an important feature of any
manned space transportation system that is developed
that it can support the in orbit infrastructure that will be
created by the Columbus programme. This will give
Europe a credible independent capability to conduct a full
range of low Earth orbit operations.
Aerospaceplane: The main activity during the 1 990's in
this area will be the development of an advanced launch
system for operation soon after the turn of the century.
The role of a manned programme in the 1990's would be
to support this activity with technology development.
Apart from the question of technical compatibility with
the extensive infrastructure Europe hopes to put in place,
there is also a question of cost. All these developments
are expensive programmes, running to several billion .
accounting units each. They are all crucial to maintain a �
European foothold in the space industry particularly the
Rew developing areas in microgravity exploitation. lt is
therefore important thatthe development funds are spent
efficiently only meeting real requirements. Hermes is not
only expensive in its own right but it is significantly affect
ing the Ariane 5 costing by increasing the l&unch vehicle
size and specification beyond what is required for its
other missions.
2.2 Support To International Space Station
With the Columbus pressurized laboratory Europe has
demonstrated thatit is possible to create a system whose
development both, enhances European goals for a mea
sure of independence and the maintenance of a competi
tive space industry, while at the same time enhancing the
overall western space capability in a significant and use
ful way. The development of a European manned launch
system offers a similar opportunity:
Europe has a need for an independent manned launch
system and manned whereas the United States has a
need for a contingency launch and crew return system.
Were the United States to develop this, then it would be
merely duplicating capabilities that it already has within
the STS system, whereas if Europe developed the system
it would provide Europe with many capabilities that it
does not have and badly needs in addition to assisting the
I nternational Space Station effort.
Jlor the safe operation of the Space Station NASA has
identified the need for a contingency return system that is
attached to the space station to allow immediate escape
from the space station and return to Earth in the event of
an emergency. The system called CERV is not (at the time
of writing) in the four baseline Space Station work pac
kages, but is the subject of an independent study and
development programme.
The provisional requirements for CERV have been
released by NASA. These include the capability to under
take the following nine mtssions:
Mission 1 - (Baseline mission) to return Station crew
to the Earth in the event of a station abort
decision.
Mission 2 Space Station Contingency, that is the pro
vision of a safe haven retreat.
Mission 3 Crew Ambulance, that is the ability to
return sick or injured crewmembers to the
earth for medical attention.
Mission 4 - EVA Crewmember Rescue, that is the
recovery of crewmembers who have
detached from the Station during EVA and
have no means of return
Mission 5 - Unmanned Delivery to the Space Station,
that is the ability to launch the CERV to the
space station by launch systems other
than the STS.
·
Mission 6 - Crew delivery to the Space Station, that is
the delivery ofcrew to the Space station in
the event of a temporary loss of STS.
Mission 7 - Space Station Cargo Return, that is the
returrr of cargo from the Station to the
Earth in an unmanned mode.
Mission 8 - Crew Rescue from Damaged STS, that is
rendezvous with a damaged but orbiting
Orbiter to recover the crew.
Mission 9 - Temporary Space Station Contingency
Depa·rture and Immediate Return.
The MRC study was aw!!re of NASA's interest in such a
system but was not familiar with the contents of the draft
specification. Thus the study derived its own set of
requirements for a Station Escape Vehicle and incorpo
rated these into the MRC design. The studies assessment
proved to match the NASA specification very closely with
the exception that Mission 4 (EVA Crewmember Rescue)
and Mission 8 (Crew Rescue from damaged STS) were
omitted. When the requirement for these missions was
known the design was revisited and it was found that
requirements from the European needs had influenced
the overall requirements such that these unforeseen mis
sions could be conducted without any alteration to the
feasibility design.
2.3 Microgravity
There are two aspects to space transportation systems,
the delivery of payloads to orbit, and the return of
payloads to the Earth's surface. Aria ne has given Europe
the first half of this but currently it has no capability for
return. This has a particular influence on Europe's ability
to do microgravity research, which currently is seriously
compromised.
Return capability is an integral part of any manned
spaceflight system. Thus it is reasonable to explore the
use of any independent European manned system to also
provide an independent microgravity research facility.
59
14. 2.4 Independent European Space Station
Europe is already examining the possibility of the estab
lishing of an independent Space Station as a long term
objective. This is understudy as an evolution of the Col
umbus programme with crew delivery by Hermes.
Should this ever be undertaken as a programme then a
rescue system similar to tile CERV (discussed above in
section 2.2) would be required. Since the MRC study
included the complete CERV requirements in the system
specification, it could of course meet this European need
when it arises.
3. REQUIREMENTS
3.1 Reference Missions
The following were the missions that were considered
when the MRC specification was determined.
3. 1. 1 Independent Missions and Technology Flights.
The first class of missions were the missions independent
of other elements in the European in orbit infrastructure.
These include the test flights, which will prove the inde
pendent launch capability, and technology proving flights
during which the various techniques required for a full
capability in manned spaceflight such as EVA and in orbit
construction. later technology flights could be used to
qualify components of the Aerospace plane or other pro
jects intended for the beginning of the next century.
Another mission that could be undertaken in an indEf.
pendent role is a guest visit to the Soviet Mir Space Sta
tion (or its successor). Whether or not this particular mis
sion is undertaken, it illustrates that a ·system such as the
MRC, or 'Hermes, w0uld give Europe the ability to partici
pate in internationc.l manned space programmes on an
equal partner basis.
3. 1. 2 Space Infrastructure Support
The main role of the MRC within the overall infrastructure
is to support the manned in orbit infrastructure. This i$
currently foreseen as having two elements, a laboratory
attached to the USA Space Station, and a European Man
Tended Free Flyer (MTFF) microgravity laboratory. later
an independent European Space Station could be envis
aged.
The MRC could have two roles associated with Euro
pean involvement in the Space Station. The first is as the
escape system (CERV) allowing the crewto return to Earth
in the event of a catastrophic Space Station malfunction
or the grounding of the Space Shuttle system for any
reason. If Europe undertook to provide this element it
would mean a continued commitment to European
involvement in the programme as (with the current MRC
specification) the life boat would probably need to be
replaced every two years.
The second Space Station role would be a second
means of crew delivery. This second access capability is
not a technical requirement of the Space Station prog
ramme although it would give a fallback mode that allows
the Space Station to continue reduced operations in the
event of another grounding ofthe STS. However the main
value of a European crew delivery mission would be for
prestige as it emphasizes the strength of its partnership in
the programme.
60
C .1. Hempsel/
The Columbus Man Tended Free Ryer has two possi
ble methods of servicing, either from the USA Space Sta
tion, or by the independent European manned launch sys
tem (Hermes or MRC). Even if the Space Station is
selected as the best operational method the independent
servicing capability is still important to-ensure Europe has
full control over this important facility. later it may prove
desirable to establish an independent European perma
nently manned space station and this will clearly need a
fully independent logistics and crew supply capability.
The European independent manned access capability
would need to support manned operations in orbit until a
fully man rated operational European aerospaceplane
exists, which,with a suitable overlap,means around 2005.
To leave the long term options open for the expansion of
the European independent activities it should be
assumed that the system shall be able to support a 1 2
man facility a s a n upper limit, while be optimized around
a 4 man station.
ECLSS Open ECLSS Closed ECLSS
Oxygen 990 500
Air makeup 400 400
Water 7670 3070
Hygiene etc. 1000 1000
Mise 100 100
Other
EVAconsumables 80 80
Personal effects 240 240
Propellant 1990 1990
Thermal fluid 20 20
Repair parts 1200 1200
Payload 3000 3000
TOTAL 16690 1 1600
There are two support roles that the MRC is intended to
undertaken. They are crew transportation and a con
tingency crew return system (lifeboat). the same roles as
envisaged for the USA/International Space Station. A
third possible role of logistics support was not included in
the requirements for the MRC alone. The reason for this
omission can be seen from consideration of the logistics
requirements for a 3 man permanently manned station.
Thus the annual requirements for supplying a perma
nent facility is well over 10 tonnes. If 4 crew rotation
flights a year are assumed (ie at 90 day intervals) then
more than 3 tonnes of payload each flight must be carried.
This would have increased the payload requirement of
the system by 300 per cent with a corresponding impact
on the overall system. lt was decided that the logistic sup
ply activity would not be included in the MRC require
ments. The available methods of conducting supply mis
sions are discussed further in section 5 below.
3. 1.3 Unmanned missions
Before the MTFF becomes operational (about 1997)
Europe's main microgravity facility will be the Eureka
platform. This is an unmanned satellite that is launched
by the Shuttle, boosts itself into a higher orbit then con
ducts around six months of microgravity experimenta
tion. lt is then recovered, refurbished and reflown with a
new payload.
However the "post-Challenger" Shuttle programme
does not appear to offer as many flight opportunities for
Eureka as originally hoped for nor is it given the priority
that Europe would have liked. Thus, there appears to be a
15. Rationale and Requirementsfor the Multi-Role Capsule
gap between Europe's desires for microgravity research
and the actual capability they possess to conduct them.
ESA have already started to explore the possibility of an
Ariane launched returnable capsule as a means to fill this
gap.
lt was decided to include the possibility of an unma n
ned microgravity version of the MRC in the specification.
This would give a substantial capability for microgravity
research which is totally under European control.
3.2 Study Goals
From the above discussion the study identified a total of
eight infrastructure roles that the Multi-Role Capsule
should undertake. These are:
i Independent European Manned Access To
Space
ii Manned Spaceflight Technology Develop-
ment
iii Unmanned Microgravity Laboratory
iv US Space Station Escape System
v US Space Station Contingency Access
vi MTFF And Polar Platform Servicing
vii European Space Station Crew Access
viii European Space Station Escape System
In addition to conducting the above roles, the study set
out with the following major goals for the system :
Early operations - lt was felt that there was a n urgent
need to start European manned spaceflight as soon
as possible. lt is clearly going to be an importantfea
ture of space capability by the turn ofthe century
and Europe has considerable catching up to do to
become a credible supplier and operator of manned
spacecraft.
Minimize development cost - As discussed above the
funds available for such a programme are likely to
be limited and the best value for money approach
needs to be adopted.
Maximize potential utlization - The main goal of the
system is to open up opportunitie!! for Europe so the
design should be such that it maximizes the poten
tial uses of the system.
4. SPECIFICATION
This section describes the main features of the technical
specification that the MRC study worked to.
4.1 Payload
The specified payload for the MRC was set as 1 500 Kg all
contained in the pressurized cabin. This figure is used to
size the MRC structure and equipment such as the recov
ery system, the capability required during an Ariane 4
launch is reduced to 1 000kg. The payload includes the
crew's personal effects and spacesuits for all the crew, but
not the provisions or personal equipment employed dur
ing the flight in the MRC itself. A cargo bay, with dimen
sions at 1 .8m x 1 m x 0.5m, is also included in the specifica
tion, capable of supporting up to 500 kg of mission
specific payload when carying a maximum crew.
The maximum crew size was specified as a nominal
four men with a maximum of six men for some missions
which do not include the use of the main cargo bay. This
figure is determined by a several independent considers-
tions. Most identified independent and other early mis
sions required a crew of between two and four men. The
longer term needs for a European independent manned
infrastructure are less clear however the specified capac
ity is the minimum to supply crew for the twelve man sta
tion, while not being oversized to support a smaller (and
more likely) three to six man station.
The crew size must also consider the lifeboat role.
There is a need for a lifeboat on the NASA Spce Station
which could have a crew ofsixto eight, as well as one any
future European independent station. A crew size of six
would allow two lifeboats to support the Space Stations
as foreseen in the next decade. Two is the minimum
number of lifeboats in any cases b�cause if the crew
member ambulance mission is undertaken an escape
provision must remain at the station. Major expansion of
the Space Station (up to 1 8 crew) could be undertaken
with only a third lifeboat. The need for consideration of
the long term is of particular importance in the case ofthe
lifeboat role. lt is an expensive item and itwould consider
ably add to expansion costs if the lifeboat system needed
replacement. With the six man crew the MRC could fulfill
the role until the in orbit infrastructure, and the launch
system operations are sufficiently advant:ed to provide
crew escape provisions by more sophisticated methods.
This could mean that MRC would be still in operational
use until the middle of the next century.
4.2 Mission
The maximum m1ss1on duration was set at six days
including any contingency, with an additional require
ment to be able to be stored on orbit, while docked to a
space_station, for a period of up to two years. The life sup
port system was required to carry consumables for 24
mandays.
The six days flight and 24 mandays consumables
requirements were determined by missions, with up to a
four man crew, for five days (plus one day contingency).
This would be sufficient for independent missions with
time for technological development activities (such as
experimental EVAs). Also early support flights with a two _
men crew would have additional contingency to resolve
teething problems associated with early facility opera
tions. The requirements for six man crew escape (or even
six man crew delivery) are well within this capability.
The two year on orbit storage time was determined by -
the lifeboat role. The technology required for the opera
tion of such a capsule after a prolonged period exposed to
the space environment is the most significant area of
technological uncertainty. The maximum proven for the
Apollo capsule was 86 days on the Skylab mission, and
the Soviet Union has been replacing the Soyuz crew deliv
ery spacecraft every six months or so. The two year
requirement is therefore a technological goal and longer
storage time would be desirable if possible.
4.3 Launch Vehicle
Ariane 4 was selected as the primary launch system. The
reasons for this choice were as follows:
* lt decouples the development of a new
launcher from the development of a new man
ned system. This considerably reduces the
technical risk in both programmes.
* The considerable development experience
61
16. with the basic Ariane would make the launcher
easier to man rate.
*
The use of Ariane 4 allows for a continuation of
commercial and unmanned support launches
by Ariane 5 in the event of a major technical
hold in any ofthe manned launches.
*
lt allows an earlier start to manned develop
ment flights. 1 993 being a possible first flight
date.
The basic philosophy in integrating the MRC with
Ariane 4 is to adopt a Soviet approach, that is the Capsule
and its crew are essentially passengers with very limited
monitoring and no control over the launch vehicle, which
is flown by ground control as with an unmanned flight.
The alternative approach used by the Americans with the
crew as pilots with a control option was not selected in
view of the extensive changes it would generate to the
existing Ariane system. lt was judged that there was little
difference in the safety of either approach.
Technically the Ariane 4 vehicle is quite suitable for
launching the MRC type system, however there would be
some alterations required. Some of these are the usual
alterations for man rating a launcher, covering the
amount and type of tele·metry, the launch abort proce
dures, and the analysis of the aerodynamics etc., of the
new payload.
In addition to these, there would be a need to
strengthen the structure of the upper two stages.
Although the quoted payload capability into low Earth
orbit (with four liquid boosters) is over 9 tonnes, in prac
tice structural limitations set an upper limit of 6 tonnes
with the currentdesign. This is a little light for a.system
meeting the specification outline and so it is assumed that
strengthening of the launcher will be required. The
impact of these changes on the payload capability is
uncertain and so the specification on the MRC was set at
7 tonnes. This was sufficient to meet the specification and
should be well within the capability of the modified
Ariane 4. Hopefully sufficient margin will remain to give
considerable orbital flexibility.
-
A disadvantage with this choice of launcher is the
restrictive diameter of the third stage (2.5 m.), wl1ich pro
vides a major configurational constraint. The configura
tion derived by the study shows that this disadvantage
can be overcome.
The payload provisions will have to be altered which
involves the addition of two new elements. The existing
Vehicle Equipment Bay (VEB) would need extensive alter
ation or replacement to accommodate the following:
*
All the payload mass is tranferred via the VEB to
the third stage.
*
The interface with MRC (including the separa
tion system) is significantly different from the
existing,interface.
* The man rating will probably involve some
changes in the electronic outfitting of the
launch system which is housed in the VEB.
The other change is the replacing of a faring with an
escape system. This would be used to pull the MRC from
the launch system in the event of an emergency requiring
a crew escape.
lt is possible that laterthe MRC would be required to be
62
C 1 Hempsell
launched on Ariane 5, sharing with another payload or
additional module (this possibility is discussed further in
section 5 below). This should not prove technically very
difficult if a special adapter is constructed between the
MRC and the Ariane 5 upper stage. The other payload
rides within this adapter in a similar manner to the Lunar
Module on the Apollo/Saturn 5.
Another possible launch system is the STS. The use of
the Shuttle would be to deliver rescue capsules to the
Space Station. These would be mounted in the STS
payload bay attached to Airborne Support Equipment
(ASE). In this role it would be launched unmanned. The
study did not consider this launch system in detail, but did
keep the MRC dimensions compatible with the payload
bay.
4.4 Interfaces
The main interfaces apart from those associated with the
launch system are those required for operations with the
Space Station/Columbus. This necessitat�s the inclusion
of a Space Station Docking/Berthing port, which has a 1 .3
m square hatch, a connection ring about 2 m in diameter
and maximum dimensions from tip to tip on the guidance
plates of about 2.3 m. This is much larger than previous
manned systems have been required to accommodate
and has a profound influence on the overall configura
tion.
The operations at the Space Station also require that
the MRC has a grapple point for the Space Station man
ipulator system (this has been assumedto be the same as
the Shuttle's RMS). Its location has to be such that the
manipulator can place the capsule on to a berthing port.
A desirable feature that was included in the MRC
specification was the inclusion of a cold gas reaction con
trol subsystem for control when close to other manned
systems to prevent damage from the hot gas thrusters.
4.5 Safety
The main safety feature of the MRC during the launch
phase would be a solid rocket escape tower of the same
type used on Mercury, Apollo, and Soyuz, as discussed in
-section 4.3 above. These have proven to be an effective
means of crew escape in the event of a problem with the
launch system, particularly on Soyuz where they have
been used during real emergencies and have saved the
crews' lives.
The provisions for decompression, and cabin environ
ment contamination rely on each crew member having a
pressure suit which would be worn during launch and
other critical operations. Because every crew member
has a pressure suit there is no provisions for Shuttle type
rescue enclosures.
Contingency supplies include survival packs, medical
packs, repair tools and a contingency allowance ofthe life
support consumables. In this regard the provisions are
very similar to the practice of Apollo and Space Shuttle.
Normal good design practice for safety is of course
assumed.lhis involves having redundancy on all the life
critical items and so far as is practicable avoid co6ocating
redundant units. Potential hazardous components that
represent either an explosion or toxicity hazard are
located outside the pressurized volume. The design
17. Rationale and Requirementsfor the Multi-Role Capsule
..
would also avoid materials that can propagate fire, out
.gas, or have other undesirable properties.
4.6 The Microgravity Laboratory
This was assumed to be a minimum modification from
the manned version. With the removal of the seats and
other systems not needed on an unmanned flight the
payload was raised to 1 .5 tonnes on an Ariane 4 launch,
still all, housed in the pressurized volume. This payload
will however need about 1 kw of power and thermal condi
tioning which will involve the incorporation of additional
systems.
5. ARIANE 5 VERSION
There are two major comt'romises inherent in the above
specification. First the maximum mission lifetime of only
5 days in orbit operation, this was deliberately set as short
as possible for the prime missions to allow the use of sim
pie storage techniques for the consumables which are
easier to design for the long on orbit storage. The second
compromise was the omission of the logistics role for the
reasons already discussed in section 3.
lt is not certain whether either ofthese are crucial omis
sions or not, but it is possible to improve the system With
an additional module. Originally the study aimed to
explore this option to demonstrate the expansion poten
tial of the MRC concept when placed on the new launch
system. However when this was under consideration the
options and possibilities that opened up were so many
and the work needed to refine the uncertain requirements
given the current definition of the infrastructure pre
cluded the derivation of a set of requirements or a config
uration within the resources allocated to the study.
-
For the study a 1 5 tonne payload capacity was
assumed. The extension options are unlikely to develop
as well as Hermes as the capabilities would be very simi
lar. Without Hermes, which drives the 21 tonne require
ment, Ariane 5 could be returned to the commercially
optimum 1 5 tonnes. Given the main MRC system "has a
mass of 7 tonnes this leaves around 7 tonnes for any
extension module.
The optional nature of an Ariane 5 version should be
stressed. The basic MRC on Ariane 4 can meet the funda
mental requirements for a European manned transporta
tion system as already discussed. If detailed considera
tion of the infrastructure requirements leads to the deci
sion that an expanded system capability has an indepen
dently justifiable role, then the option is open.
The study foresaw three main missions that an
expanded MRC could undertake, in addition to some sec
ondary missions. Each tended to drive requirements in a
different direction and it was not possible to p,rove these
could be met by a single system by generating a feasibil-
ity design.
-
The first mission as an extended independent flight for
technology development. The need for such missions
given the Columbus programme is small unless special
orbits, or some other special requirements. The most
likely configuration for this mission would be a pressured
module which would about double the habitable volume,
increasing the consumables and power to give a mission
life of around three weeks.
The second mission is a MTFF servicing mission (also
applicable to an independent space station) delivering
both the crew and the supplies in one launch. For this mis
sion an Ariane 5 launch was used to launch the MRC and
an extension module together. This module would need
both a pressurized and external payload area. A first esti
mate ofthe payload capacity suggests that such a module
should easily carry the 3 tonnes identified for this mission
in section 3.1 .2.
the third mission was the servicing of unmanned plat
forms particularly the Columbus· Polar Platform. Tll�
polar orbit reduces the available payload but in this case
there is no need for a pressurized area and if optimized for
this mission, an MRC and extension module could have a
payload of over 2 tonnes, which is consistent with mis
sion requirements.
6. PROGRAMME
The study assumed a specific programme for develop
ment and utilization. This is shown in Fig.2. The prog
ramme assumed a maximum utilization of the potential
by undertaking all the design missions.
Anoopa<eplane
-
Polor l'lat l'lo@.
Rncue Capsule
- ·
Columbus Pros
Manned ViRc
U.:ape Cap.,le
Spare Station Pfos.
lotdependent
Mic:ro@ravity
MRC OPERATIONS PROGRAMME
. .
no "'
. .
......� F1l
IUUI •I$'
"
. . . .
n � n rt
. .
Fn ,. ,
. .
f'l& F'lO
--- MM TOt()£0 F'A£E F.YDI
.
"'
. . . . . .
Ftt Fn rn Fn ,.. Flt
Test flights
,. 8 c 0 � � :, .....NE s MOD
F
�:s
�mp-nt l'lo@. �����:=;������=;=�=��������-=�
11 11 to tl tl tl M ts t6 t7 M tl 00 01 Ol Ol 04 OS Ol 07
BRfflSH
AEROSI'Aa
-
"INbllledi:Pfoer--
- - ·
---
---
---
(.................
�........ .......,...
n.pt......,....,....F1 - �
Fl ·Moc,..,....,
··
.. . -
I MRC DEVELOPMENT PROGRAMME I
.... .... 1tN 191)
Fig.2 MRC Programme
MRC ·
I
I
....
The development programme from the beginning of
Phase B to launch of the first test flight is just over four
years long. This may appear short when compared with
the durations proposed for other programmes (such as
Hermes or Columbus), but the com plexity ofthe system is
not as great and this programme is considerably longer
than the time spent developing similar systems in the
1 960's.
63
18. lt was assumed that the programme would start in the
fou rth quarter of 1 988 which leads to the first flight in
1 993. This flight would be unmanned but fly the manned
version, the second flight is also unmanned by flys the
special microgravity laboratory version. Then in the
fou rth quarter of 1 993 the fi rst manned flight is underta
ken as a further test of the system. A second manned
development flight is conducted in 1 994 before the sys
tem is judged ready for operation.
The overal l operations programme indicates the sys
tem wou ld _have about flights a year over a fifteen year
period. The main·use would be as an escape system for
the various space stations with eleven of the thirty flights.
The table 1 gives more detail of the flights. lt a lso iden
tifies three contingency missions that may cal l for cap
sules to be constructed and held in readiness.
TABLE I Mission Model
No. Date Crew Launch Mission
Development
STM 1 991 Structural testing
EM System Development
OM 1 992 System Qualification
Flight Models
F1 1 993 0 A4 Development
F2 1 993 0 A4 Microgrvity
F3 1 993 2 A4 Development
F4 1 994 4 A4 Development
FS 1 994 0 A4 Microgrvity
F6 1 994 4 A4 Independent mission
• (e.g. Mir Visit)
F7 1 99S 0 A4 Microgravity
F8 1 99S 0(6) A4 ISS Rescue capsule
F9 1 996 0 A4 Microgravity
F10 1 996 314 A4 ISS
.
Visit (System
Demonstration)
F1 1 1 997 314 A4 ISS Visit (Crew Supplement
For MTFF Operations)
F12 1 998 0(6) A4 ISAS Rescue Capsule
F1 3 1 998 2 AS AS Development
F14 1 998 2 AS MTFF Service
F 1 S 1999 0(6) A4 ISS Rescue capsule
F16 1 999 2 AS MTFF Service
F17 2000 2 AS Polar Platform Service
F18 2000 2 A5 MTFF Service
F19 2001 0(6) A4 ISS Rescue Capsule
F20 2001 2 AS MTFF Service
F21 2002 0(6) A4 ISS Rescue Capsule
F22 2002 2 AS MTFF Service
F23 2003 0(6) A4 ISS Rescue Capsule
F24 2003 2 s MTFF Service
F25 2004 0(6) A4 ISS Rescue Capsule
F26 2004 0(6) A4/AS ESS Rescue Capsule
F� 200S 2 s � Polar Platform Service
F28 2006 0(6) A4 ISS Rescue Capsule
F29 2006 0(6) A4 ISS Rescue Capsule
F30 2007 0(6) A4/A5 ESS Rescue Capsule
Contingency capability
C1 1 996 4 A4/AS Crew Supply for ISS & ESS
C2 1 999 on 2 AS MTFF or PP service
C3 200S on 2(6) A4/AS Aerospaceplane Rescue
After a further independent manned flight, probably a
guest visit to the MlR station, the fi rst Space Station sup
port flight occurs at the end of 1 995 and is an unmanned
ll)ission to supply the first lifeboat just before permanent
manned operations begin. This lifeboai is assumed to be
replaced every 18 months. Two visits are also included in
the programme, one, after a years operation of the Space
Station facility, as a goodwil l visit and technical demonst
ration. The second visit sends a fou r man crew to expand
the Space Station capability during the in orbit construe-
64
C.. .1. Hempse/1
tion and commissioning phase of the MTFF, when the
workloa.d is likely to be heavier than the standard Station
Crew c�uld be expected to handle.
Once i n operation two servicing missions a year would
be conducted in the prog ramme. An Ariane 5 version is
assumed, which effects the programme in that a n addi
tion technology development flight using the Ariane 5 at
the end of 1 997.
The unmanned flights of the microgravity laboratory
are assumed at the rate of one a year after the first fl_ig ht
in 1 993. These stop in 1 996, in anticipation of the MTFF
becoming operational in the following year which would
become Europe's main microgravity Laboratory.
7. HERMES
Since support of the manned in orbit infrastructure is the
primary objective of the Hermes system (Fig.3), a com
parison of Hermes and the MRC is appropriate. The ques
tion that needs to be addressed is does Europe need
both? The answer is somewhat complex.
The Hermes concept is for a spaceplane which is
placed into orbit by Ariane 5, it would then return i n the
same manner as the Space Shuttle gliding to a landing on
a conventional runway. lt would then be turned rou nd for
a reflight.
The Hermes in its most recent form is optimized for the
servicing of the MTFF or European Space Station. Its crew
is now three reduced from an earlier fou r or six, this was
partly to reduce mass and partly to allow the crew to be
located in an ejectable cabin duri ng launch. Behind the
cabin is a pressurized payload area, which has 18 cubic
meters for payload storage and 8 cubic meters l iving
space. Behind the payload area is the airlockthat also has
the docking port for connection to the facility to be ser
viced.
The total payload capabiity is quoted as 3 tonnes but
this i ncludes margins and payload packaging and this
gives a useful payload of 2 1 00 kg. lt has a long mission
duration capability of three months.
7.1 Launch Vehicle Impact
As with a l l aerospace plane solutions its mass com pared
with its payload mass is high, the total mass is around 2t"
tonnes for about three tonnes of payload including crew.
This has meant that it has greatly exceeded the original
capability planned for Ariane 5 ( 1 5 tonnes) this has lead to
a continuing series of proposals to increase Ariane 5
payload mass to chase Hermes' growing mass.
The current margin (as available to the a uthor at the
time of.writing) on the Hermes system is 2.6 tonnes in 1 8
ton nes (Launch mass less payload) or 1 4.5 per cent. For a
system at this level of definition this is a narrow margin
and there must be some risk that the overall mass budget
of 21 ton nes may be exceeded. This means that Ariane 5
may need further u prating or that the payload capacity of
Herrn.es would need to be reduced. Neither a desirable
option.
7.2 Space Station
There a re two potential missions that could be underta-
19. Rationale and Requirementsfor the Multi-Role Capsule
Fig.3 Hermes
ken by a European manned launch system. One is guest
visits, acting as a secondary crew deliv_ery system. There
is very little difference i n the effectiveness of either
Hermes or MRC to fulfill this role.
The second is a lifeboat for contingency crew return.
Hermes is not suitable for this job for several reasons:
*
lt is not designed for extended i n orbit stays
(modification to achieve this carry a high
technological risk)
*
lt requires a skilled pilot to fly it during re-entry
*
lt is an expensive asset to perform this role
*
lt will not be available early enough
By contrast MRC has the lifeboat role as one of its primary
missions and has none of the above problems.
7.3 Columbus Support
Whether the Columbus remains as the MTFF or expands
to an independent European space station there are four
main support roles, Module delivery, Crew transporta
tion, Logistics supply and Rescue. There are several
options (see Fig.4) though all need the development of a
specialist upper stage for the delivery of the main Colum
bus elements, and the development of some form of bal
listic capsule. The latter is an important point, that a
IIODUU c••• 1.00rmcs ..,...DI:UVIRY D&UVIRY DIUVIRY
���
I
�A w.......�
-
... .....
""""...
B �� �u-n �IAWOTIC
.,....... -
... .........
c
�- W:�.... &_.. �IAWOTIC
... ..... ...
.........
D
� �.......... & �.-................. . ..wmc ....... IAUJOnC
... CAPIULI ., CAPOULI
Fig.4 European Space Station Transportation Options
lifeboat system would require development in addition to
Hermes·
·
if a n i ndependent European station were to be
established. This additional cost would be essentially the
same as the development cost of the complete MRC sys
tem as outlined in this paper.
65
20. Both MCR and Hermes can act as a crew transportation
system, the main difference being in the number of crew.
The MRC maximum crew capability is set as six (the orig
inal Hermes crew size) as com pared with the current
Hermes crew of three. For servicing the MTFF three is
probably sufficient, however a crew of only three, espe
cially if one needed to be a trained pilot, would restrict
European options at the turn of the century.
Another fundamental difference between Hermes and
MRC is that Hermes has a significant logistics payload
capability ( 1 8 m2,3 ton nes), whereas the MAC is some
what limited (1 m2, 500 kg). The MAC can match the
Hermes performance with an extension module and a n
Ariane 5 launch, s o the systems could b e judged roughly
equivalent (remembering that MRC requires only 1 5
tonne payload capacity Arian e 5). Whether three ton nes is
sufficient depends on the complexity of the eventua l sys
tem to be serviced. For a man tended system or a small
station of two or three men it is probably sufficient, how
ever a larger system would be more effectively supplied
by an Ariane 5 Transfer Stage delivered logistic module.
7.4 Independent Operations
Both Hermes and MAC would g ive Europe the ability to
demonstrate a manned spaceflight capability. They are
both able to conduct the main identified m issions, i.e.
technology demonstration and development a guest visit
to Soviet Station. Hermes does have one-advantage over
the baseline MAC in that longer flight times a re possible
which can be a n advantage for some of the technology
development. If this longer mission is felt necessary then,
as with the logistics capability, an Ariane 5 and an exten-
sion module would address this disparity.
·
7.5 Technology Development
One of the prime features of the Hermes system is the
large amount of new technology that would need to be
developed to complete the programme. E u rope wil l need
to expand the technologies that its industry is capable for
exploitation in the early years of the next century, particu
larly by the Aerospaceplane (e.g. HOTOL). Table 2 shows
the developed technolog ies against three main i nfras
tructure program mes; Colu mbus, MAC and Hermes.
The Columbus program me, which is not primarily
intended as a technology development in its own right,
never the less does provide a degree of appropriate
technology development. The MAC would provide some
additional technolog ies but in some a reas the experience
gained. HERMES provides a m uch ful ler range of technol
ogy development. lt should be noted that the same or bet
ter range of technology advancement could be obtained
from a smaller pure experimental vehicle without
attempting to meet infrastructure roles.
( .1. Hemp�el/
TABLE 2 Technology Development
Technology Columbus MRC Hermes
Space Medicine X X X
Robotics X
EVA X X
Hypersonics I X
Fuel Cel l X
ECLSS X X X
Turnaround X
Flight Avionics I X
In Orbit Comms X X X
Advanced Prop.
Cyro Tank!Struct.
(X = extensive I = limited)
lt is a debatable point as to whether a fu l l scale manned
vehicle would be needed to provide the necessary
technology advancement for a n aerospaceplane. The
conclusions of the HOTOL study tend to argue against it.
8. CONCLUSIONS
This paper intended to explain the rationale for conduct
ing the M AC study and explain th� derivation of the sys
tem specification that was used as the target for the tech
nical design. lt is assumed that Europe requires a manned
programme giving independent access to the in orbit
i nfrastructure.
The requirements were set around the performance of
a ball istic capsule launched on Ariane 4. In keeping with
the conclusion with American studies conducted in the
sixties, particularly those leading to the demise of the X-
20 Dyna-Soar programr.,e, it was found that the perfor
mance of ballistic capsule on an expendable launch sys
tem is about three times better than an aerospaceplane as
wel l being more cost effective with low launch rates. Thus
the MRC can offer effective infrastructure support, while
using a smaller and existing launch system. This reduces
the technica l risk, development and operation costs, as
well as being operational m uch earlier.
There a re a number of options in the longer term with
rega rds to support of independent European facilities and
with the technology developments which will be required
for the support of the advanced launchers. lt was not
withi n the scope of the MAC study to trade off these
options, but even if it is not judged that a vehicle meeting
the MAC specification can contribute to these areas there
are sufficient unique roles for such a vehicle to provide a
justification for its development.
This paper represents the author's private work and the views expressed in the paper are those of the author and do not necessanly
represent those of British Aerospace plc.
.. .. ..
21. Journal ofthe British Interplanetary Society, Vol 42, pp. 67-81, 1989
MULTI-ROLE CAPSULE SYSTEM DESCRIPTION
C.M.HEMPSELL AND RUSSELL J. HANNIGAN
British Aerospace plc, Space and Communication Division, Stevenage, Herts.
The Multi-Role capsule (MRC) is a concept for a recoverable capsule capable of working in a manned and unman
ned mode. lt was the subject of a feasibility study within British Aerospace. lt has a two module configuration, a
Descent Module contain the crew and major systems and a jettisonable Service Module with eq"uipment that is
only required in orbit. lt would be launched on Ariane 4, and be capable of carrying up to six men or 1 500 kg of
payload
The paper describes the feasibility design at system and subsystem level.
1. INTRODUCTION
The M u lti-Role Capsule (MRC) concept is the result of a
study into the potential of a European manable capsule i n
the context of the a nticipated 1 990's infrastructure. This
paper describes the main technical features of the M RC
feasibility design that was produced to demonstrate the
viability of the concept. The study goal was to produce a
feasibility design of sufficient detail that reasonably accu
rate assessments of
i) The technologies i nvolved
ii) The performance,
iii) The cost,
could be made. To accomplish this the feasibility design
was taken down to unit level for all subsystems. lt should
be noted that few trade offs were conducted during this
process, therefore the results presented here are deemed
to represent a workable system, although not necessarily
an optimum.
The M ulti-Role Capsule was designed to u ndertake
eight infrastructure roles. They include all the European
requirements for pay1oad recovery and manned space
access. They also i nclude all the missions that NASA has
identified for the Crew Emergency Rescue Vehicle (CERV)
element of the Space Station. the CERV was not in the ini
tial Space Station plans, but is now u nder study i n the
.United States and is generally agreed to be an essential
part ofthe Space Station program me. The eight roles are :
I ndependent European Manned Access
ii Manned Spaceflight Technology Develop-
ment
iii Unmanned M icrogravity Laboratory
iv US Space Station Escape System (CERV)
v US Space Station Contingency Access
vi MTFF and Polar Platform Servicing
vii European Space Station Crew Access
viii European Space Station Escape System
There are clearly advantages to multi-role systems.
Although the development process is a little more com
plex set of system requirements, and the resulting pro
duct is a little off optimum for a ny particular m ission, the
i ncreased utilization of the final product can lead to very
substantial savings.
2. SYSTEM REQUIREMENTS
The MRC study sta rted by merging the m ission require
ments of the identified infrastructure roles to· obtain the
overal l specification the capsule would need to meet. The
main requ irements identified are discussed in this sec-
tion.
·
The in-orbit mass wil l require to be u nder 7 tonnes to
meet the likely performance -of Ariane 4. There is also a
maximum diameter requirement of 4 meters. This is
determined by a need to restrict the hammerhead on the
launch system and also to aid integration into space sta
tion configurations.
The crew should nominally be fou r for a launch case
with six during an emergency return only. The provision
should also be available for between 260 and 500 Kg of
payload.
The active l ife should be five days with an additional
day capability for contingency (six days in total ). In addi
tion to this a two year on orbit lifetime in a storage or
hibernation mode was specified. This was primarily a
technologicial concern and if later studies show this could
be extended then this would be highly desriable.
The system would be required to deliver crews to and
return them from orbit and orbiting space systems nota
bly space stations. lt is required to support limited EVA
activity, one nominal and one contingency two man EVA
being specified.
The system was specified as a semi-ba l listic vehicle
with a nominal splashdown in the ocean. In a contingency
case the capsule should be able to touchdown on land
without major injury to the crew. The landing accuracy
during an automatic re-entry should be to within two
kilometers of a designated point. Recovery is to be
accomplished with a single ship and helicopter.
A m ore detai led account of the rationale for the deriva
tion of the system requirements is given in reference 1 .
3. DESIGN
3.1 Configuration
The MR� has a two module configuration as shown i n
67
22. Figs. 1 and 2. A Descent Module that has the pressurized
section and is the-se::tion that returns from orbit. Attached
to the rear of the Descent Module is the Service Module
which contains equipment which is only required while in
orbit and can be jettisoned before re-entry. The Service
Module also acts as the adapter to the VEB on the Ariane
launch system.
Solor
Descent Module
Separaboll
Acceaa Hatch
Fig.1 General View of MRC
Data Relay Satellite
Link Anlenna
Pilot olCommander
V.ewports
Thruster Pods
Figu re 1 shows the orbital flight configuration of the
MRC with the arrays and a ntenna deployed. The nominal
attitude would be Sun locked, with the Sun along the Z
axis, that is full on solar array (which has a fixed position).
When manoeuvres or other tasks require a different
attitude the spacecraft is powered from batteries which
can then be re-charged duri ng periods of Sun pointing. In
this respect the MRC has adopted a very similar strategy
to the Soviet Soyuz spacecraft.
Solor Amy
Smice Module 1 Pesceut Module 1
Fig.2 Three Views of MRC Orbital Configurations
3. 1. 1 Descent Module
This is a cone shaped structure 4 meters in base diameter
and 3.6 meters high. At the front end is a Space Station
compatible docking port. Two pods behind the port con
tain the main thrusters and recovery parachutes. Another
unpressurized area atthe base houses the propulsion and
ECLSS consumables.
The majority of the Descent Module is devoted to the
pressurized cabin . This is divided i nto three com pa rt-
68
C. M. Hempsell & R.J. Hannigan
ments, the forward compartment which Plouses the galley
and hygiene. The mid compartment contains the main
crew a rea. The rear cabin houses the batteries and a mis
sion specific payload area 1 .8 x 1 .5 x .75 meters. In the
Space station lifeboat role (whether the International/US
Space Station or an independent European Station) the
payload bay would house an additional two seats allow
ing a total six crew to return in the event of a n emergency.
The main crew area in the mid cabin can contain up to
fou r seats. Two of these are nominally passenger seats
and two a re nominally pilot seats althc: Jgh the MRC can
be flown by one man or even ful ly automatical ly. The two
pilot seats have forward facing viewports and a control
console. Most of the MRC equipments are housed i n this
a rea in a U shaped equipment bay which act as a floor and
lower wal ls to the mid cabin area. A side hatch opens into
this a rea which is used for access into tlie vehicle on the
launch pad, and as the egress/ingress for EVA while in
orbit. The side hatch also achieves compliance with the
Space Station safety requirement for two independent
methods of entering any area.
The docking port, which is compatible with the stan
dard Docking/Berthing port on the International-United
States Space Station, drives the configuration of the for
ward section of the capsule. The guidance vanes on the
port are placed symmetrical ly to aid the re-entry
aerodynamics this means the hatch is place� at an angle
of 22.5 deg rees to the spacecraft axis. This a lso effects the
docking angle and meansthe internal local vertical is 22.5
deg rees away from the local vertical of the Space station
system that has the docking port guidance vanes set
asymmetrically.
The microgravity laboratory version would be unman
ned, however the main configuration and equipment
remains essentially the same. The main experiments
would be mounted in racks which are mounted in the
same locations as the seats. Up to six ofthese racks can be
carried, each carrying up to 200 Kg. The forward com part
ment which normally houses the hygiene and galley
would in this case carry secondary experiments.
Figure 3 shows the interior arrangement of the fou r
m a n transport, with two payload racks mounted i n the
payload a rea. The view also shows the propellant, and
gas storage tanks in the lower u npressurized area.
Fig.3 Interior View of 4 Man Version
23. Multi-Role Capsule System Description
3. 1.2 Service Module
The service module is a cylinder 4 meters i n diameter and
1 metre high. lt houses the cold gas reaction control sys
tem, the solar array, the DRS iink antenna, and some other
electronic boxes.
The solar array has three ridged panels (five in the mic
rogravity laboratory version) and deploys after separa
tion from the launch system along the X axis. This direc
tion was selected because it does not impact on the over
a l l diameter in the YZ plane which allows the M RC to be
easily integrated i nto the Spa�e Station a rchitecture.
The DRS Link antenna is also deployable after separa
tion form the launch vehicle . lt swings through 1 80 Deg. ·
such that the support boom is pointing along the Z axis. A
two axis pointing mechanism is then used to keep the
antenna pointing at the DRS satellite. The antenna can not
track the DRS u nder all attitude conditions the field of
view being over a complete hemisphere. However the link
with DRS is only intended for use when the mission activ
ity demands it, so this restriction is not considered critical .
The Service Module is-jettisoned before the de-orbit
burn, by firing the fou r explosive bolts that hold it to the
Descent Modu le.
3.2 System Budgets
3.2. 1 Mass
The most critical aspect of the concept was judged to be
the system mass so a significant proportion of the study
effort was devoted to a detailed mass aualysis. Table 1
gives the subsystem level breakdown for the Ariane 4
launched manned version of the capsule.
The study placed this major emphasis on achieving a
realistic mass estimate for two reasons. Firstly, mass has
been the main "Achi lles Heel " for past proposals for man
ned launchers and must be considered a key issue in any
assessment of feasibility. I n particular the selection of
design launcher was judged to i ncreas-e "the mass sen
sitivity.
The second reason for the attention to mass is that
si nce the parametric costing techniques that were to be
used are largely dependent upon mass. These techniques
are proven to be surprisingly accurate providing the mass
data used accurately reflects the final system mass. Thus
the accu racy of the cost estimate largely depends upon
the real ism of the mass estimate.
From the start the study maintained a multi level mar
gin approach with an identified margin at every level
where a requi rement specification wil l eventual ly be
placed ; that is at system, subsystem and equipment
levels. The system budget in Table 1 shows two col umns,
the first has the raw estimated mass for each su bsystem
( being the addition of the unit mass estimates) the second
colu m n showing the subsystem masses after unit and
su bsystem level margins have been added giving the
su bsystem specification mass. A detailed mass break-
down is g iven i n Appendix A.
-
The total available margin (raw estimate to system
specified maximum) is 22 per cent of the 7 tonnes availa
ble. Of this 8 per cent was been distributed to the subsys
tems and equipments. The total margin held by the sub-
TABLE 1 System Mass Breakdown
SUBSYSTEM SUBSYSTEM SUBSYSTt:M SUBSYSTEM
ESTIMATE SPECIFIED MARGIN
MASS (kg) MASS (kg) %
Mechanical
Structure 895 1 000 1 1
Thermal Protect 631 730 14
Thermal Control 64 80 20
Mechanisms 313 350 1 1
Propulsion 1 64 1 0 22
POPS 64 70 9
Recovery 236 270 1 3
Mech.Fittings 21 25 1 6
Electrical
Data Management 48 55 1 3
S-Band Comms 1 8 20 1 0
Audio Comms 24 30 20
Ku Comms/Radar 1 28 145 1 3
Guilde.Nav. & Con 70 80 1 2
Power 271 310 13
Habitability
ECLSS 185 210 12
Galley & Hygiene 71 90 22
Fittings 237 270 1 2
Loose items 75 85 1 2
Caution &Warning 36 45 20
TOTAL DRY MASS 3551 4075
Consumables 930 977 5
Payload 1 000 1 000
Margin 1 519 (22%) 948 ( 1 4%)
SPEC MASS IN ORBIT 7000 7000
Escape Tower 756 950 20
LAUN.CH MASS 7756 7950
systems is generally g reater than 1 0 per cent and i n many
cases exceeds 20 per cent typical ly 5 per cent of this is
held at the subsystem level and the rest distributed to
equipment, based u pon their level of definition. The con
sumables have a 5 per cent allocation as these are consi
dered wel l defined. The payload allowance has no margin
as the specified is assumed to contain its own margin.
The study concluded that these margins were suffi
ciently healthy to give a high degree of confidence in the
feasibility of an in orbit specification mass of 7 tonnes.
3.2.2 Power
Table 2 shows the system level power bullget indicating
the average power consum ption for each subsystem. A
similar margin philosophy was used for power as
described for the mass budget. A 10 per cent margin is
held at subsystem level with specification values bein.g
rounded u p to the nearest 5 watts. A minimum of 1 0 per
cent was deemed necessary at system level in fact the
study had identified a 16 per cent margin.
4. LAUNCH SYSTEMS
4. 1 Ariane 4
Ariane 4 was selected as the primary launch system for
the MRC. The reasons for this choice are that it allows for
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